1. Field of the Invention
The present invention relates to an infusion apparatus capable of informing its operator of the time for replacing the parts such as a battery of the apparatus.
2. Description of the Prior Art
An infusion apparatus is used for infusing a medication fluid into a vein of a patient. There has been conventionally known in general an electromechanical positive pressure peristaltic type apparatus provided with a pump mechanism 8 as shown in FIG. 5. The pump mechanism 8 has a construction as follows. There are provided n number of fingers 83(1), 83(2), 83(n) driven by n number of cams 82(1), 82(2),. . . , 82(n) shifted in phase between every adjacent ones around a shaft 81 driven by a stepping motor (not shown). The fingers 83 are driven to move their ends 83a in a direction perpendicular to an administration tube 84. By peristaltically pressing the administration tube 84 downward against a door 85 with the fingers 83(1), 83(2), . . . , 83(n), a medication fluid supplied from an administration set (not shown) into the administration tube 84 is transferred.
FIG. 6 shows a block diagram of an infusion apparatus of the above-mentioned type, while FIG. 7 shows a flowchart of the operation of the infusion apparatus.
Referring to FIG. 6, a power supply switch, designated by numeral 1, turns on the power to the infusion apparatus when pressed. An alarm display unit, designated by numeral 2, displays 11 the alarm messages detected by the infusion apparatus. A display unit, designated by numeral 3, displays all the program data concerning fluid infusion such as fluid delivery rate, scheduled fluid volume, and accumulated fluid volume input to the infusion apparatus. A key panel, designated by numeral 4, has thereon numeral keys for inputting values of the fluid delivery rate and the scheduled fluid volume to set up values of operation spend and operation time for a pump mechanism 8, control keys for input assistance, a start key for starting the operation of the pump mechanism 8, a stop key for stopping the operation of the pump mechanism 8, and a call-up key for displaying the accumulated volume of fluid delivered and the like. An operation state indicator, designated by numeral 5, is a lamp that indicates which state the infusion apparatus is currently in among the states of alarm, fluid infusing operation, and operation stop. A lid opening detector, designated by numeral 6, detects whether or not the door 85 has come into the open position in order to set the administration tube 84 into the pump mechanism 8. The lid opening detector 6 is also necessary for stopping the operation of the pump mechanism 8 and generating an alarm when the door 85 is inadvertently opened while the pump mechanism 8 is in operation. An upstream occlusion sensor, designated by numeral 7, detects a pressure-reduction state due to the occurrence of any abnormality (e.g., clogged filter) in an administration set disposed between a medical solution container and the infusion apparatus, and is used to stop the operation of the pump mechanism 8 with generation of an alarm. The pump mechanism 8 includes a stepping motor. A motor driving circuit, designated by the numeral 9, drives the above-mentioned stepping motor according to a pulse output from a CPU 18. A pump mechanism rotation detector, designated by numeral 10, through the amount of rotation at the pump mechanism 8 detects that an incremental unit (e.g., 1 ml) of fluid has taken place, and then informs the CPU 18 of it. A downstream occlusion sensor, designated by numeral 11, detects a pressure-rise state within the administration tube between the infusion apparatus and the patient due to the occurrence of any abnormality such as occlusion, and is used to stop the operation of the pump mechanism 8 with generation of an alarm. An air bubble detector, designated by numeral 12, detects that air bubbles more than a prescribed amount have entered the administration tube. When this is detected, an alarm is generated while the operation of the pump mechanism 8 is stopped to thereby prevent the bubbles from entering into a patient's body. A battery-voltage detector, designated by numeral 13, detects any battery-voltage drop of a lead battery (not shown) used as a backup of an AC power supply. When this battery voltage drop is detected, the operation of the pump mechanism 8 is stopped while an alarm is generated. The lead battery is charged by a power supply circuit 15 when the infusion apparatus is in operation on the AC power line. A buzzer driving circuit, designated by numeral 14, generates a buzzer sound for informing doctors and nurses of the fact that the infusion apparatus has entered into the alarm state. A power supply circuit, designated by numeral 15, supplies power to all the circuits of the infusion apparatus. An analog-to-digital converter, designated by 16, converts the voltage resulting from a voltage conversion of a current supplied to the motor of the pump mechanism 8, the air bubble detector output level, the battery voltage level, and the like into digital values, and inputs them into the CPU 18. A panel lock switch, designated by numeral 17, serves to render the panel key and the power key input-inhibited so that the infusion apparatus will not be operated without permission by unauthorized personnel. A CPU (central processing unit), designated by numeral 18, controls the operation of the infusion apparatus. A RAM (memory section), designated by numeral 19, includes a first storage section for storing fluid delivery rate and scheduled fluid volume and a second storage section for storing various types of data used for arithmetic operation by the CPU 18. A ROM (read only memory; program section), designated by numeral 20, contains a program for operating the CPU 18.
The following describes the operation of the present infusion apparatus with reference to the flowchart shown in FIG. 7.
When the power to the infusion apparatus is turned on at step S1, it is determined at step S2 whether or not the pump mechanism 8 is in operation. When the pump mechanism 8 is not in operation, a request for inputting values of the fluid delivery rate and scheduled fluid volume takes place at step S8. Therefore, a doctor or nurse who intends to use the infusion apparatus inputs values of the fluid delivery rate and scheduled fluid volume at step S9 according to the desired medication fluid and medical treatment. When the pump mechanism 8 is to be operated, the program flow proceeds from step S10 to step S11 to operate the pump mechanism 8 by a key input. Then the pump mechanism 8 starts to deliver the fluid at the fluid delivery rate. When the pump mechanism 8 is in operation at step S2, the program flow proceeds to step S3. When it is detected by the pump mechanism rotation detector 10 that an incremental unit (1 ml in this case) has taken place, a value smaller by one than the current scheduled fluid volume is set up as a renewed scheduled fluid volume at step S4. When the power to the infusion apparatus is turned off by means of the power switch at step S5, the operation of the pump mechanism 8 is stopped at step S12 and the power is turned off to make the infusion apparatus enter into an off state to wait for the turning-on of the power at step S1. When it is determined at step S6 that the scheduled fluid volume has reduced to zero or when a request for stopping the operation of the pump mechanism 8 takes place due to a key input or the occurrence of an alarm, the program flow proceeds to step S7 to stop the operation of the pump mechanism 8. Then the program flow returns to step S2 to wait for an input of the next values of the fluid delivery rate and scheduled fluid volume.
The infusion apparatus requires periodical maintenance service a part of which requires service personnel to grasp the use condition of the infusion apparatus. For instance, there is the lead battery for backing up the AC power supply as an important component of the infusion apparatus. The lead battery gradually loses its charge capacity in the course of repeating charge and discharge operations which results in a reduced operable time and a need for replacement. Therefore, in order to determine the time for replacing the battery, the service personnel have recorded the total time of use of the infusion apparatus for the medical treatment to measure the degree of the deterioration of the charge capacity. However, on the same time of use basis, the power for charging the battery differs between the case where the battery has been used actually for operating the pump and the case where the infusion apparatus has been left unoperated while receiving a power. When the total time of use of the infusion apparatus includes the period of time in which the infusion apparatus is operated on the battery, the battery is not charged but discharged during the period of time. Therefore, it has been impossible to correctly measure the lifetime of the battery at all times only by the time of use of the infusion apparatus. In order to correctly perceive the lifetime of the battery, it is necessary to recognize the rate of the period of time in which the pump had actually operated and the rate of the period of time in which the power is supplied from the battery with respect to the total time in which the power is supplied to the infusion apparatus. Among the parts other than the lead battery, there are several parts requiring replacement after being used for a certain time. However, it is impossible for the service personnel who is neither a doctor nor a nurse to clock the time in the field where the infusion apparatus is used while referring to the use condition of the apparatus. It is also impossible for the doctor or nurse who is administering a medical treatment to clock the time. Meanwhile, it has been absolutely necessary to perceive the correct data in order to maintain the infusion apparatus serving as a therapeutic apparatus always in the best condition. As described above, the conventional infusion apparatus has been provided with an insufficient function in regard to the maintenance service for maintaining the quality of the infusion apparatus.